Bicycle frame



FIG. 1 is a perspective view of a bicycle frame, showing my new design;

FIG. 2 is a top-plan view thereof;

FIG. 3 is a right side-elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof; and

FIG. 7 is a left side-elevational view thereof. 

The ornamental design for a bicycle frame, as shown. 